using existing satellite radio antenna

I had a pioneer dvd player put in my truck, but they weren't able to use the factory satellite radio antenna... Is there a way I can use that instead of having 2 satellite radio antennas on my truck? If so, where is the wire for the factory antenna so I can splice it.
2006 silverado ext cab lt3

All the shark fin antennas have three wires coming out of them. There is a plug right over your head, with less than one foot of lead from the antenna. This is the way it's assembled, and nessesary to un-plug for paint or antenna replacement. I assume that one wire is Onstar, one XM, and the third is possibly Nav. If you find an adaptor plug, please post. I want to use that antenna for my portable/MP3 XM unit.